They have their own sense of humor and intelligent wit, are incredibly loyal and should be reserved with people they don't know, coupled with a decent guarding streak.
Wow I met an aussie like that once, and I've been wondering if that's part of the breed! This woman used to come volunteer at the rescue shelter I volunteer for, and she would leave her troop of four dogs in the large exercise area while she was there. One of the dogs was a handsome blue merle aussie. He was
sweet as pie when his owner was around, but if you went near that exercise area when she wasn't there, he was a regular beast (barking and snarling). lol
As to the topic of the thread, I don't own a mastiff yet but there is one I intend to adopt as soon as I can, named Opie (he's the dog in my avatar). He's a Fila mixed with something else, maybe Cane Corso. Before Opie I thought mastiffs were cool, but I NEVER thought about owning one. I thought they were too big, too stubborn, not for me, blah blah. Opie has changed all that though. I have never had a dog love me so much. My lab, Daisy, doesn't come near me unless I have food, or she wants to go out. The rest of the time she's sleeping someplace, or in the kitchen begging whoever is in there for a treat. Opie, however, can't get enough of me. He's a great big snuggle dog, and I go in his run and sit there with him on my lap for usually around two hours. I just LOVE dog cuddles, so its funny that the dog I currently own is the Anti-Cuddle.
I like Opie's loyalty, and intelligence. To some people Opie might not SEEM intelligent because he isn't like a border collie, but he's always observing and figuring out stuff. He's innovative and quite outside the box. For example, for some reason Opie just can't understand how to pick up a Frisbee like a normal dog, so he broke a hole in the middle and picked it up that way.
Also, Opie really isn't a dog to act rashly. He evaluates the situation first, and then reacts accordingly. Although, he does react rashly to lawn mowers, I learned that last weekend. We were in the exercise area and one of the staff started mowing the grass near the fence with a push mower and Opie threw himself at the fence a couple times (normally he likes the guy just fine, I guess he just doesn't like the mower). I had to distract him and go on the opposite side of the exercise area until the guy was done because I didn't want Opie to bend down that chain link fencing!
Its always SOMETHING new with these guys. I love it! I will never be without a mastiff in my life again. I have been researching different mastiff breeds, and I am really crushing over Cane Corsos right now. I was also looking at Filas. They are really something quite different from any other dog breed I've met. I may own one sometime, but I don't think I'm quite ready yet.